fix(input-password-toggle): improve screen reader announcements (#30885)

Issue number: resolves internal

---------

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## What is the current behavior?

The `ion-input-password-toggle` button uses `role="switch"` with
`aria-checked`, causing screen readers like VoiceOver to announce both a
state ("On/Off") and an action ("Show/Hide password"). This results in
confusing, redundant output such as "On, Hide Password" or "Off, Show
Password".

## What is the new behavior?

The password toggle button now uses `aria-pressed` instead of
`role="switch"` with `aria-checked`. Screen readers announce the
action-based label ("Show password" or "Hide password") along with the
pressed state, and properly announce state changes when the button is
activated.

## Does this introduce a breaking change?

- [ ] Yes
- [X] No

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## Other information

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screenshots of how the component looks before and after the change. -->

[Old
Preview](https://ionic-framework-git-main-ionic1.vercel.app/src/components/input-password-toggle/test/basic)

[New
Preview](https://ionic-framework-git-fw-6920-ionic1.vercel.app/src/components/input-password-toggle/test/basic)

Current dev build:
```
8.7.15-dev.11766421552.180757ca
```